Choose the correct alternative.
1. | Alloys of metals usually have less resistivity than that of their constituent metals. |
2. | Alloys usually have much higher temperature coefficients of resistance than pure metals. |
3. | The resistivity of the alloy manganin is nearly independent with an increase of temperature. |
4. | The resistivity of a typical insulator (e.g., amber) is less than that of a metal by a factor of the order of 10 22 / 10 23 . |
A negligibly small current is passed through a wire of length \(15~\text{m}\) and uniform cross-section \(6.0\times10^{-7}\) m2, and its resistance is measured to be \(5.0~\Omega.\) What is the resistivity of the material at the temperature of the experiment?
1. | \(1\times 10^{-7}~\mathrm{\Omega m}\) | 2. | \(2\times 10^{-7}~\mathrm{\Omega m}\) |
3. | \(3\times 10^{-7}~\mathrm{\Omega m}\) | 4. | \(1.6\times 10^{-7}~\mathrm{\Omega m}\) |
A silver wire has a resistance of at , and a resistance of at . The temperature coefficient of resistivity of silver is:
1.\(0.0033 \ ^{o}C^{-1}\)
2. \(0.039 \ ^{o}C^{-1}\)
3.\(0.0039 \ ^{o}C^{-1}\)
4.\(0.033 \ ^{o}C^{-1}\)